Some harms of beta-carotene supplementation may persist after discontinuing use

November 30, 2004

A 6-year follow-up of a large, randomized trial in people with a history of smoking has found that the overall harm associated with beta-carotene supplementation on cardiovascular disease mortality disappeared quickly after participants stopped taking the supplements. However, the risk of lung cancer may persist, especially in females and former smokers, according to the study in the December 1 issue of the Journal of the National Cancer Institute.

In the 1980s, preliminary studies suggested that beta-carotene might have chemopreventive abilities, so two large, randomized trials were begun to test the supplement's effect on lung cancer among cigarette smokers: the Alpha-Tocopherol Beta-Carotene (ATBC) Trial, which was conducted in Finland, and the Beta-Carotene and Retinol Efficacy Trial (CARET), which was conducted in the United States. Both trials were stopped after evidence accumulated that the supplements were associated with an increased risk of lung cancer. In CARET, the group that received beta-carotene supplements had a 28% greater incidence of lung cancer and 17% more deaths from all causes compared with the placebo group.

To determine if the effects of beta-carotene supplementation continued after participants stopped taking the supplements, Gary E. Goodman, M.D., of the Fred Hutchinson Cancer Research Center in Seattle, and colleagues followed the more than 18,000 participants in CARET for 6 years after the trial was stopped, until the end of 2001.

The increased risk of cardiovascular disease mortality quickly disappeared after participants stopped taking the supplements. However, women had a higher risk of death from cardiovascular disease or from any cause than men. In addition, the incidence of lung cancer and deaths from all causes decreased but did not disappear completely after the supplementation ceased. The excess risk of lung cancer was restricted primarily to females and former smokers.

"When chemoprevention agents are administered to large, healthy populations, it is necessary to document long-term safety, efficacy and, importantly, the duration of the beneficial (or adverse) effect," the authors write. "This is especially true when the basic underlying molecular and genetic mechanism of the agent is unclear. The results of CARET and ATBC emphasize that chemoprevention trials require careful monitoring of all disease endpoints ... even after the study intervention is discontinued."

In an editorial, Anna J. Duffield-Lillico, Ph.D., and Colin B. Begg, Ph.D., of Memorial Sloan-Kettering Cancer Center in New York, discuss these latest findings and their relation to other prevention trials using beta-carotene. In addition, they write, "These findings suggest that the adverse effects of high-dose beta-carotene on lung cancer incidence and overall mortality ... may be related to the pharmacologic doses of beta-carotene used and the resultant supra-physiologic serum concentrations of beta-carotene."
-end-
Contacts:
  • Article:
  • Editorial: Christine Hickey, Department of Public Affairs, Memorial Sloan-Kettering Cancer Center, 212-639-3627, hickey1@mskcc.org

    Citations:
  • Article: Goodman GE, Thornquist MD, Balmes J, Cullen MR, Meyskens Jr. FL, Omenn GS, et al. The Beta-Carotene and Retinol Efficacy Trial: Incidence of Lung Cancer and Cardiovascular Disease Mortality During 6-Year Follow-up After Stopping Beta-Carotene and Retinol Supplements. J Natl Cancer Inst 2004;96:1743-50.
  • Editorial: Duffield-Lillico AJ, Begg CB. Reflections on the Landmark Studies of Beta-Carotene Supplementation. J Natl Cancer Inst 2004;96:1729-31.

    Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage. Visit the Journal online at http://jncicancerspectrum.oupjournals.org/.

    Journal of the National Cancer Institute

    Related Lung Cancer Articles from Brightsurf:

    State-level lung cancer screening rates not aligned with lung cancer burden in the US
    A new study reports that state-level lung cancer screening rates were not aligned with lung cancer burden.

    The lung microbiome may affect lung cancer pathogenesis and prognosis
    Enrichment of the lungs with oral commensal microbes was associated with advanced stage disease, worse prognosis, and tumor progression in patients with lung cancer, according to results from a study published in Cancer Discovery, a journal of the American Association for Cancer Research.

    New analysis finds lung cancer screening reduces rates of lung cancer-specific death
    Low-dose CT screening methods may prevent one death per 250 at-risk adults screened, according to a meta-analysis of eight randomized controlled clinical trials of lung cancer screening.

    'Social smokers' face disproportionate risk of death from lung disease and lung cancer
    'Social smokers' are more than twice as likely to die of lung disease and more than eight times as likely to die of lung cancer than non-smokers, according to research presented at the European Respiratory Society International Congress.

    Lung cancer therapy may improve outcomes of metastatic brain cancer
    A medication commonly used to treat non-small cell lung cancer that has spread, or metastasized, may have benefits for patients with metastatic brain cancers, suggests a new review and analysis led by researchers at St.

    Cancer mortality continues steady decline, driven by progress against lung cancer
    The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

    Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
    The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

    Lung transplant patients face elevated lung cancer risk
    In an American Journal of Transplantation study, lung cancer risk was increased after lung transplantation, especially in the native (non-transplanted) lung of single lung transplant recipients.

    Proposed cancer treatment may boost lung cancer stem cells, study warns
    Epigenetic therapies -- targeting enzymes that alter what genes are turned on or off in a cell -- are of growing interest in the cancer field as a way of making a cancer less aggressive or less malignant.

    Are you at risk for lung cancer?
    This question isn't only for people who've smoked a lot.

    Read More: Lung Cancer News and Lung Cancer Current Events
  • Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.